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"He's a predator, he's a repeat offender," she told the Channel Nine program.

"The only reason he hasn't offended in the past 20 years is because he was locked safely behind bars. He can't get out. I'll do anything I can to keep him locked up."

Some friends and family members aren't aware of what Charlotte endured as a child, she said. Breaking her silence was part of a bid to ensure Guider, who will soon be eligible for parole, isn't released from prison.

Guider's modus operandi was to put the prescription drug Normison in Coca Cola and give it to his victims, Detective Chief Inspector Darren Sly said.

"He chose his victims, the young children, very carefully and in particular he preyed on single parents," he said. "He was able to gain their trust very quickly and access their children."

After he was arrested, police found thousands of photographs depicting Guider's abuse of nine girls and two boys.

He had also collected newspaper clippings about Samantha's disappearance, making him a person of interest in the investigation.

On August 19, 1986 she left her home in Bondi Beach and was never seen again.While in prison serving a sentence for 75 child sex abuse charges, Guider formed a friendship with a fellow prisoner and eventually made a gruesome confession.

Frank Soonius, who was serving an 11-year sentence for drug trafficking, told 60 Minutes that Guider admitted to snatching Samantha and taking her to a shed, where she was drugged and molested.

Chantelle was one of Michael Guider's last victims. She has pleaded he never be released from prison. Photo / 60 Minutes

Chantelle was one of Michael Guider's last victims. She has pleaded he never be released from prison. Photo / 60 Minutes